Substrates such as glass substrates for hard disks and glass substrates used in devices such as liquid crystal displays are expected to be flat with high accuracy. Thus, these substrates are planarized by polishing. Whether or not planarization is accomplished successfully and efficiently is affected by abrasive grains contained in an abrasive agent.
Thus, various abrasive agents and abrasive grains have been proposed. For example, an abrasive agent containing cerium oxide (CeO2) as abrasive grains exhibits a high polishing rate and thus has been used widely. Japanese Patent No. 3927270 is an example of related art.
Because cerium is a rare earth metal, however, alternative abrasive agents with a high polishing rate as substitutes for cerium oxide (CeO2) have been desired.